Road construction



2 Sheets-Sheet 1 Filed July 26, 1961 Oct. 26, 1965 J, JENSEN 3,213,768

ROAD CONSTRUCTION Filed July 26, 1961 2 Sheets-Sheet 2 United States Patent 3,213,768 ROAD CONSTRUCTION Jens Lauritz Jensen, Meilgade 47, Aarhus, Denmark Filed July 26, 1961, Ser. No. 126,978 Claims priority, application Denmark, July 27, 1960, 2,965/60 4 (Ilaims. (Cl. 94-14) The invention relates to a road construction for roadways, runways, and the like, and it consists of pre-manufactured concrete or reinforced concrete slabs placed on supports. It is easy to make as usually it needs no preceding preparation of the ground. It will imply special advantages, especially in the case of soft ground or ground frozen solid in the winter.

Previously, pre-manufactured slabs were placed directly on the ground as the slab distributes the load of the vehicles to such an extent that the specific pressure on the ground is not so big that the slabs are pressed down in it. These slabs have, however, been used only for provisional airports as a more intensive trafiic will soon bring the individual slabs out of position and especially out of level.

It has been proposed to raise the slabs over the ground level by placing them in a line, side by side, on two heavy concrete rails or walls, one in each side of the road, and if necessary on intermediate rows of supports. As in the case of the slabs directly on the ground it is also in this instance a drawback that the stratum frozen in the winter brings slabs and rails, or supports, out of position in relation to one another which happens especially during the thawing of the freezable stratum and then results in such influence that considerable and lasting damage is caused.

The purpose of the invention is to remedy these drawbacks by ridding the touchy parts of the road completely of the freezable stratum. To that end the road construction according to the invention is characterized in that the pro-manufactured slabspossibly by means of girdersrest on the rows of frost-proof piles or pillars (e.g. of concrete) placed there in advance and reaching down through the freezable stratum and anchored in solid and frost-free strata whereas the slabs are kept free of the freezable stratum. Therefore, they will not be displaced when the frozen stratum thaws and the other parts of the road are not in contact with the frozen stratum and will, consequently, not be offset by it.

Each slab can be supported at three or more points, or along the sides, as it rests on girders which again rest on the piles or the pillars, and in order to prevent the slabs from being displaced horizontally they may each, according to the invention, have supporting projections along the vertical sides of the pillars, such as arms or collars. The slabs may, according to the invention, have, further to the faces bearing against the pillars, at least one projection turning downwards and e.g. being calotte-shaped and resting on the ground.

The last-mentioned projection contributes in the support of the slabs, but resting on the surface of the ground it will not freeze together with the freezable stratum but will in the lateral direction be secured by the pillars.

In order to increase the strength of the individual slabs, they may, according to the invention, have bracing ribs from one of the two kinds of projections to the other.

These bracing ribs can be placed in such a manner that they can also transfer the main part of the horizontal forces in the slabs as, according to the invention, the ribs are positioned so that they stretch mainly from horizontal supporting projections along the edge of the slabs to a centrally positioned vertical supporting projection under the centre of the slabs.

"ice

According to the invention each slab may have an electric heating element built-in and connected to electric cables in the side of the road. Thus the road can be kept frost-free, and snow and ice covering the road will thaw without the assistance of any snow-clearing service. It is often impossible for such a service to do its work fast enough, and in many countries it does not operate on Sundays and holidays. Ditches and other measures for drainage of the road are superfluous, as its underside will always be kept dry by the wind which may pass freely under it.

The narrow space between the slabs, the so-called expansion joints, may be filled in some known way with asphalt or other water-tight substances or organs so that precipitation will drain off over the lateral edge of the slightly curved roadway.

Whereas road markings must be renewed often owing to wear as they are made on the spot and as it must be possible to wipe them out in case of alterations to the road or trafiic regulations, it is, according to the invention, possible in the case of this road construction to build in or furnish the surface of the road with e.g. road stripes, skidding stripes, and acoustic danger signals at the factory, thus ensuring long durability. In case the above equipment is to be removed from the road, the entire slab is renewed.

According to the invention, each slab may during the manufacturing process be furnished with a wearing surface insulating against moisture, and this insulating layer may be applied with greater care and under more ideal conditions at a factory where this preparation can take place indoors and more conveniently by the aid of the requisite machinery than on site. Furthermore, the preparation as well as the finishing preparation can take place without the usual pressure of the traffic which leaves the least possible time for road works. The slabs should, according to the invention, meet this demand by the trafiic fully, as they are not repaired but renewed.

Moreover, road side fences may, according to the invention, be clamped to the sides of the slabs or be made as constituent parts of the roadway element.

In order to absorb stresses in the longitudinal direction of the roadway, caused e.g. by braking, over a great number of piles, the individual roadway element may be assembled to larger units, e.g. by means of cables passed through cable ducts in the roadway elements so that the cables run parallel with or diagonal to the longitudinal direction of the roadway, by means of spigot-and-socket joining of steel reinforcement, by means of bolting, or in some other known manner. By this also a reduction of the groove problem is obtained. This problem is also reduced by the fact that after a suitable storage period the pro-manufactured roadway elements will have gotten over the usual setting contraction before the installation.

On the drawing an example of a road construction made in accordance with the invention is shown.

FIG. 1 shows part of a road construction in perspective,

FIG. 2 shows, also in perspective, a slab forming part of the same construction and FIG. 3 shows the same slab seen from below in a slanting position.

On a number of piles 1 of concrete or some other material, which may either be rammed down or poured in holes in the ground, a number of transverse supports 2 made of reinforced concrete and with a curvature corresponding to the shape of the roadway have been positioned. Rows of slabs 3 have been placed on these supports and are held in position in the longitudinal direction by these supports 2 whereas they are held in position in the lateral direction by a detached road side fence 4 consisting of a horizontal concrete beam placed on a number of piles 5 which have been rammed so deep in the ground, as is also the case with the piles 1, that they have passed through the strata 6 frozen in the winter, and are solidly anchored in the strata below.

Each slab has a hole 7 in the centre of its overside in which there is a ring 8 by means of which the slab can be lifted from its place.

The underside of the slab is equipped with a number of ribs 9 for bracing. These ribs stretch from the edge of the slab towards a calotte-shaped projection 10 in the centre of the slab. The slab can rest on the ground by the aid of this projection, but this must not necessarily be so.

The slab, which is finished at the factory, has an electric heating element built into its surface coating, consisting of a material insulating against moisture, or immediately under this coating, and the heating element is connected electrically with cables 11 in an external cable box 12 on the fence 4.

It is assumed that the upper layer of steel reinforcement in the slab can be used as heating element.

By electric heating it is not only possible to thaw snow and ice covering the road so that clearing away of snow and gravelling are made superfluous, but it is also possible to dry the road comparatively quickly after precipitation.

Such pre-manufactured slabs can be richly varied with regard to surface equipment. Thus they can be equipped with grouted in road stripes, marking of pedestrian crossings, acoustic road marking in the form of transverse grooves of varying size, etc., just as it will be possible to make the surface granulated or grooved or in some other way skid-proof.

The advantage of the road construction is, according to the invention, first and foremost that the nature of the ground is of no importance and that generally it will not be necessary to move any earth before the road is constructed.

Besides, the road can be constructed across areas fiooded part of the year. Drainage or sewerage is not necessary. The water runs off the roadway at the side fence 4 which has vertical grooves 13 on its inside to ensure the drainage.

The road is easy to repair. Repairs are effected simply by renewing one or more slabs 3. Thus the periods during which the roadway is blocked to the trafiic are limited to a minimum.

The underside of the road is kept dry by the wind and is therefore not exposed to decomposition. Rainwater may, furthermore, drain off through the intervals 14 between the slabs 3, but generally it will be preferred to fill the expansion joints with asphalt so that the overside of the roadway forms a water-tight whole.

In the same way as the piles are introduced in holes in the underside of the fence 4 the piles 1 are introduced in holes in the transverse supports 2. Instead these supports can be laid in grooves on top of the piles 1 or the piles may have vertical guide pins introduced in holes in the supports 2.

' Under the middle of each slab 3 sand or pebble gravel can be spread over the ground in advance in support of the calotte-shaped part of the slab.

Even if each slab can be made with a considerable thickness and strength so as to be able to carry the traffic for which the road is destined, it will be possible to save substantial amounts during the construction, according to the invention, as excavation and sewerage are avoided, and the result is a road which is not exposed to the well known frost injuries occurring every year when the frozen stratum thaws.

What I claim and desire to secure by Letters Patent is:

1. A roadway construction comprising piles extending into the ground sufficiently below the frost line to provide road support and having upper end portions extending above the ground surface, beams supported on the upper ends of said piles and extending transversely of the roadway at selected spaced intervals, said beams having a rectangular cross section with fiat upper surfaces and opposed vertical side surfaces, a plurality of rectangular premanufactured concrete slabs each having a length slightly less than the center-to-center spacing of said beams and a width which is a unit fraction of the width of the roadway, each of said slabs extending between and being supported by two successive beams and having end portions which are notched to provide fiat lower surfaces resting on the flat upper surfaces of said beams and vertically downwardly extending shoulders engagable with said side surfaces of said beams, a plurality of said slabs being laid side-by-side to make up the desired width of the roadway, said slabs having on their under sides downwardly projecting integral ribs extending generally lengthwise of said slabs and having vertical end faces which are coplanar with said shoulders and abut said vertical side surfaces of the beams at the ends of the respective slabs, means confining said slabs at the sides of said roadway against laterally outward movement, said slabs being spaced from adjacent slabs in both a longitudinal and a transverse direction to provide narrow spaces between adjacent slabs, and compressible material filling said spaces to provide water tightness while permitting limited movement in both longitudinal and transverse directions arising from expansion and contraction of said slabs.

2. A roadway according to claim 1, in which said means for confining said slabs at the sides of the roadway comprises curbs extending longitudinally of the roadway at each side thereof and projecting above said slabs and piles supporting said curbs above the ground and extending into the ground sufficiently below the frost line to provide permanent support.

3. A roadway according to claim 1, in which each slab is formed in its upper face with a central recess and in which a lifting ring for said slab is anchored in said recess.

4. A roadway according to claim 1, in which said beams are arched in a direction longitudinal of the beams and transverse of the roadway.

References Cited by the Examiner UNITED STATES PATENTS 510,831 12/93 Beeching 9427 663,199 12/00 Shepard 9427 776,419 11/04 Platt 94-11 930,153 8/09 Butz 94-11 1,254,401 1/18 Cole et a1. 94-11 1,331,265 2/20 Kelly 94-31 1,426,003 8/22 Orrock. 1,435,618 11/22 Newell 9411 1,726,222 8/29 Gregg 94 31 X 1,729,256 9/29 Honberger 94-19 X 1,891,595 12/32 Grierson 52173 XR 2,042,377 5/36 Bamber 9419 2,042,964 6/36 Rinehart 945 3,023,986 3/62 Nallinger 244-114 FOREIGN PATENTS 818,983 6/37 France.

226,057 12/24 Great Britain.

290,091 5/28 Great Britain.

310,131 4/29 Great Britain.

CHARLES E. OCONNELL, Primary Examiner.

JACOB L. NACKENOFF, Examiner. 

1. A ROADWAY CONSTRUCTION COMPRISING PILES EXTENDING INTO THE GROUND SUFFICIENTLY BELOW THE FROST LINE TO PROVIDE ROAD SUPPORT AND HAVING UPPER END PORTIONS EXTENDING ABOVE THE GROUND SURFACE, BEAMS SUPPORTED ON THE UPPER ENDS OF SAID PILES AND EXTENDING TRANSVERSELY OF THE ROADWAY AT SELECTED SPACED INTERVALS, SAID BEAMS HAVING A RECTANGULAR CROSS SEFCTION WITH FLAT UPPER SURFACES AND OPPOSED VERTICAL SIDE SURFACES, A PLURALITY OF RECTANGULAR PERMANUFACTURED CONCRETE SLABS EACH HAVING A LENGTH SLIGHTLY LESS THAN THE CENTER-TO-CENTER SPACING OF SAID BEAMS AND WIDTH WHICH IS A UNIT FRACTION OF THE WIDTH OF THE ROADWAY, EACH OF SAID SLABS EXTENDING BETWEEN AND BEING SUPPORTED BY TWO SUCCESSIVE BEAMS AND HAVING END PORTIONS WHICH ARE NOTCHED TO PROVIDE FLAT LOWER SURFACES RESTING ON THE FLAT UPPER SURFACES OF SAID BEAMS AND VERTICALLY DOWNWARDLY EXTENDING SHOULDERS ENGAGABLE WITH SAID SIDE SURFACES OF SAID BEAMS, A PLURALITY OF SAID SLABS BEING LAID SIDE-BY-SIDE TO MAKE UP THE DESIRED WIDTH OF THE ROADWAY, SAID SLABS HAVING ON THEIR UNDER SIDES DOWNWARDLY PROJECTING INTEGRAL RIBS EXTENDING GENERALLY LENGTHWISE OF SAID SLABS AND HAVING VERTICAL END FACES WHICH ARE COPLANAR WITH SAID SHOULDERS AND ABUT SAID VERTICAL SIDE SURFACES OF THE BEAMS AT THE ENDS OF THE RESPECTIVE SLABS, MEANS CONFINING SAID SLABS AT THE SIDES OF SAID ROADWAY AGASINST LATERALLY OUTWARD MOVEMENT, SAID SLABS BEING SPACED FROM ADJACENT SLABS IN BOTH A LONGITUDINAL AND A TRANSVERSE DIRECTION TO PROVIDE NARROW SPACES BETWEEN ADJACENT SLABS, AND COMPRSSIBLE MATERIAL FILLING SAID SPACES TO PROVIDE WATER TIGHTNESS WHILE PERMITTING LIMITED M OVEMENT IN BOTH LONGITUDINAL AND TRANSVERSE DIRECTIONS ARISING FROM EXPANSION AND CONTRACTION OF SAID SLABS. 